Sunday, August 15, 2010

Constipation: When the "going" gets tough

One of the more common “sick cat” calls we receive at the clinic is about straining in the litter box. Knock wood here, this is not a problem I’ve had with my own cats. (Note to Marta, Momma Cat, Butters, and the rest of you in the cattery....let’s keep it that way too!)

Constipation is the general term for the condition where your cat is unable to pass a complete bowel movement or does this with great difficulty.

Most cats have one to two bowel movements every day. Some cats go more or less than this. However, if your cat has not had a bowel movement in three or more days it can indicate a problem. While constipation is more common in cats 8 years old and older, it can occur at any age.

Not only is constipation uncomfortable, if it is left untreated, with time it can progress into more serious conditions such as obstipation and megacolon.

In the case of obstipation, your cat's colon is blocked and it is unable to have a bowel movement.

Megacolon, the most extreme of the 3, is a term used to describe a very dilated, flabby, colon that is not able to contract. This usually occurs secondary to chronic constipation and retention of stool, but may also occur due to a congenital problem. Eventually, with the colon unable to contract, so much stool is accumulates in the colon, it reaches a size that cannot pass through the pelvis.

In my earlier blog entry “These stones aren’t rolling” I mentioned that it is sometimes difficult to know why your cat is straining in the litter box because urinary inflammation, urinary blockage, constipation, colon inflammation can all result in this symptom.

Another symptom that may fool you as to what is going on is to see diarrhea associated with straining in the litter box. How can a cat be constipated if it has diarrhea? The hard, dry stool sits in the colon and causes irritation resulting in fluid being produced. This fluid mixes with the surface of the stool, softening it and allowing it to pass past the constipation.

So you can see, it’s extremely important for you to have your cat examined so we can determine what the problem is and how to treat it.

In many cases, the veterinarian can feel if constipation is present by the size of the colon and the way the stool feels when palpating here. Sometimes an accurate evaluation is difficult because your cat may be too tense or too overweight for the colon to be felt. In these cases, x-rays are very helpful in diagnosing constipation.

There are many causes for constipation in cats.

Dehydration is one of the most common causes. Today’s cats evolved from desert-living ancestors so they are very good at reclaiming fluid back into their system after it is processed by the kidneys. Thus, they do not need to drink as much water as you and I, or our other pets do. However, water is still an essential part of your cats’ diet. Potential causes for dehydration may be due to your cat not liking the taste of the water; water that is not fresh, unclean or too small or deep water dishes, or water in locations the cat does not like to be in (busy or noisy areas, areas where it can be disturbed by other pets). In addition, the presence of “water-wasting” conditions such as diabetes or chronic kidney disease can cause your cat to urinate out more fluid than it is it taking in, eventually leading to dehydration.
Litter box conditions can be a factor in constipation.

Many cats, including yours, are creatures of habit and will not defecate when in unfamiliar surroundings, such as during a move to a new home, or even if you’ve simply moved the litter box to a new location. Be careful when you change brands of cat litter. Some finicky cats will refuse to use the box if they don't like the type of litter. In addition, cats are very clean creatures and if presented with a full (“dirty”) litter box, they may try to hold a bowel movement and move on to a different location (think of what you do in a public restroom when you find the stall particularly unclean). The urge to defecate can be overridden voluntarily, so your cat may try to hold a bowel movement rather than use a box they are unhappy with. This can lead to a buildup of fecal matter in the colon, which will harden and cause constipation.

In addition to being at risk from dehydration due to “water-wasting” diseases; older, less active cats experience reduced bowel activity and the muscles of the abdominal wall may weaken.

Obese cats, and cats that do not exercise are also more likely to suffer from constipation

There are many other Factors such as painful defecation due to anal sac problems; tumors that can cause strictures (narrowing) of the colon; pelvic fractures that heal in an abnormal way and reduce the width of the pelvis, cats that don’t eat well can be constipated because with less food going in, there is less stool build up to naturally stimulate defecation and the stool remains in the colon longer and becomes drier and harder to pass, while foreign objects can cause constipation, they will usually make your cat ill long before constipation might occur.

Before your cat can be treated, we must confirm that constipation is the cause of your cats straining in the litter box, then determine the severity of the condition, whether or not damage to the colon has occurred, and if/how disease or environmental conditions that are contributing to your cats constipation.

While every cat does not need every test, it becomes very important to look for an underlying cause rather than simply treat symptoms if constipation is a recurring problem, or if we see the more serious obstipation or megacolon. In these cases it is very important to do blood and urine tests as well as x-ray.

Treatment of your cats constipation depends on the severity of the condition. Often, the starting point is to rehydrate your cat. Intravenous hydration may be required in severe cases. An enema may be needed for milder cases of constipation. In some cases, such as obstipation or megacolon, where there is a tremendous amount of hard, dry stool your cat will have to be anesthetized, not only to remove the stool but for its comfort..stool removal in a very obstipated cat can take time and be painful. In severe cases, surgery may be required to remove part of the colon.

Once your cat has been treated and is back home, make sure that it has plenty of fresh water. Feeding the right food is important, and will vary depending on the case. In general, canned food with its increased moisture content will be the starting point, and the type from there will be determined on other health factors. While fiber is helpful for some cases of constipation, the added bulk may cause more problems with difficult stool passage than it has benefits, we will be able to determine what is better for your cat. There are other ways to soften stool without bulking it, this can include Lactulose and Miralax, again they should not be used unless recommended based on your cats circumstances. Lastly, a motility drug such as cisapride can help intestinal motility so that once the stool is softened, it can be passed.

In the 20 years I’ve practiced, we now have a better understanding of constipation, how underlying diseases and environmental conditions contribute, and better diets and treatment options, and earlier intervention, even the most severe cases of constipation, obstipation and even megacolon have become more readily managed medically rather than surgically.

For the rare case that cannot be controlled medically, there is a surgical option called subtotal colectomy where the colon is removed. Cats are amazing creatures and typically have responded well, many times with normal stools and defecation.

In this case, there is stool in the colon but overall, it is not an excessive amount. The problem here is that the first 4 pieces of stool have lined up side-by side instead of single file. The bony pelvis cannot expand so the stool cannot enter the pelvic canal. This cat needed stool softener and stool removal.

Obstipation. Notice the larger amount of stool and the larger sized pieces of stool compared to the x-ray above.

Obstipation. This cat is likely to develop megacolon if there are repeatable episodes. Notice how the stool has compacted into a few very large sections that are too large to pass even with the help of an enema.

This cat needed rehydration, a stool softener, and anesthesia for the stool removal procedure.